Build: Fix csharp version update in release.yml

[alexbarev]

This PR addresses the issue of using an outdated version in the C# release CI job by implementing the changes outlined below.

Before:

• The actions/checkout@v3 action was set to use the default branch that triggered the workflow. I believe this was the root cause of the issue, as this branch (main-dev) had an outdated VERSION file.
• Version information was manually extracted from the VERSION file.

After:

• Specified the main branch for actions/checkout@v3 to ensure the use of project files updated by semantic-release.
• The CI job now relies on the updated version in nuget-package.props, which is set by update_version.sh. Manual extraction from the VERSION file has been eliminated.

[ashvardanian]

:tada: This PR is included in version 2.5.1 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: